Refuse collection loading and packing mechanism



June 21, 1966 H. BEROLZHEIMER REFUSE COLLECTION LOADING AND PACKING MECHANISM 5 Sheets-Sheet 1 Filed July L3, 1961 N 15 .w 3 l I .1 .TXQ l {N Ahormys.

vJ1me 1966 H. BEROLZHEIMER 3,257,012

REFUSE COLLECTION LOADING AND PACKING MECHANISM Filed July L5, 1961 5 Sheets-Sheet 2 BY 20hr [Ir/fir June 21, 1966 H. BEROLZHEIMER 3,257,012

REFUSE COLLECTION LOADING AND PACKING MECHANISM Filed July L5, 1961 5 Sheets-Sheet 3 June 21, 1966 H. BEROLZHEIMER 3,257,012

REFUSE COLLECTION LOADING AND PACKING MECHANISM Filed July L3, 1961 5 Sheets-Sheet 4 INV EN TOR.

flan/y fieral a'nel; BY

park ('arzer Alla/way.

June 21, 1966 H. BEROLZHEIMER 3,257,012

Filed July 13, 1961 Q Q o m it INVENTOR. k flew/y fierol luimel;

"a R BY k 5 (arzzr Afforneys.

United States Patent 3,257,012 REFUSE COLLECTION LOADING AND PACKING MECHANISM Henry Berolzheimer, 8620 S. Dorchester Ave., Chicago, 1]]. Filed July 13, 1961, Ser. No. 123,903 1 Claim. (Cl. 214-82) This invention relates to refuse collection units, and particularly to such a unit in which refuse is continuously compacted between a packer plate and an ejector-packer plate throughout the loading cycle.

Accordingly, a primary object of this invention is to provide a refuse collection unit in which refuse loaded into the unit is compacted by a packing mechanism against a combination ejector-packer plate throughout the loading cycle, the packing mechanism remaining at the loading area to thereby permit substantially continuous dumping of refuse into the packing mechanism so as to eliminate the time previously required for the packing mechanism to traverse the length of the refuse storage body during .the continuous packing operation.

Another object is to provide a refuse collection unit, as described above, in which the ejector-packer plate starts the loading cycle adjacent the loading area and packing mechanism, said packing mechanism including a packer plate, and exerts an active packing force against the refuse deposited between it and the packer plate during the loading cycle.

Another object is to provide a refuse collection unit in which the ejector-packer plate is forced rearwardly by the packing mechanism against the resisting action of hydraulic pressure to thereby provide a uniform, continuous compacting pressure automatically throughout the loading cycle.

Yet another object is to provide a refuse collection unit in which the reacting force of the ejector-packer plate can be positively increased at any time in the loading cycle to thereby exert increased packing pressure on the refuse.

Another object is to provide a refuse collection unit in which raised body dumping is eliminated, thus eliminating problems of balancing ofthe unit, permitting a lighter chassis to be used, and enabling the unit to be used in low overhead clearance environments.

A further object is to provide a refuse collection unit having means for side loading in addition to all of the above mentioned features so that the unit can be operated as a side loader, a rear loader, or as a combined side and rear loader.

Another object is to provide a refuse collection unit in which alignment of the ejector-packer plate is maintained by one or more generally vertically, centrally located hydraulic ram cylinders acting in conjunction with guide means disposed on either side thereof.

Still another object is to provide a refuse collection unit in which the ejector packer plate need traverse the length of the refuse container or body only once during each normal complete loading cycle of the unit, yet optionally the plate can be moved forward or rearward in large or small increments at will to exert increased crushing pressure as needed.

Yet a further object is to provide a refuse collection unit in which the features of the ejector-packer plate and continuous compaction of the load throughout a complete loading cycle are usable with either a batch-type packer plate, or a continuous loader, such as an orbitally moving bucket elevator.

Yet another object is to provide a tailgate for a refuse collection unit which has a small amount of side mechanism to thereby provide a hopper of maximum width and capacity. Such a wide hopper is desirable because the Patented June 21, 1966 wider the hopper the larger the object which it can receive without prior size reduction.

A further object is to provide a simple hydraulic circuit for activating the packing mechanism in the tailgate and the ejector-packer plate, and for elevating the tailgate,

the circuit utilizing only one basic valve which need be only slightly modified to accomplish all functions.

Yet a further object is to provide a refuse collection unit having an elevating tailgate in which only two cylinders are needed to run the packer plate and operate the tailgate.

Another object is to provide a refuse collection unit having a tailgate which may be loaded from a low point to thereby reduce manual lifting of garbage cans or other containers, speeds operation, and reduces operator fatigue.

Still another object is to provide a refuse collection unit having a dumping mechanism which is basically much simpler than the conventional hoist arrangements whereby maintenance is materially reduced.

Other objects and advantages will become apparent upon reading the following description of the invention.

The invention is illustrated more or less diagrammatically in the accompanying drawings, wherein:

FIGURE 1 is an elevation with the parts broken away for purposes of clarity of a refuse collection unit embodying my invention;

FIGURE 2 is an elevation of the rear of my refuse collection unit showing the tailgate in an elevated position;

FIGURE 3 is a section taken substantially along the line 33 of FIGURE 1 with parts omitted for clarity;

FIGURE 4 is a top plan view of a refuse collection body with parts omitted for clarity;

FIGURE 5 is a rear view with parts omitted for clarity of the refuse collection unit body showing the track mechanism for guiding the packer plate;

FIGURES 6, 7, 8 and 9 are views illustrating the operation of the packing mechanism;

FIGURE 10 is a schematic view of the hydraulic system for-the combination ejector-packer plate and the tailgate mechanism;

FIGURES 11, 12 and 13 are schematic views of three operating positions of the main hydraulic control valve;

FIGURE 14 is a view taken substantially along the line 1414 of FIGURE 11; and 1 FIGURE 15 is an elevation of the rotating valve member in the main hydraulic valve illustrated in FIGURES 11 through 14.

Like reference numerals will be used to refer to like parts throughout the following description of the drawings.

Referring first to FIGURE 1, my refuse collection unit is indicated generally at 10. It consists essentially of a cab 11, a chassis 12, a body or refuse storage container 13, and a tailgate 14. The tailgate contains a packing mechanism which will be described in more detail hereinafter.

The body is formed by a front plate 16, side walls 17 and 18 (see FIGURE 4), bottom plate 19 and top wall 20. A side loading door is indicated at 21 near the front end of right side wall 18. Location of the side wall in this position permits my refuse collection unit to be utilized as a side loader as well as a rear loader.

My unique combination ejector-packer plate is indicated generally at 22. It includes a vertical, movable wall 23 which traverses a path between the dotted line position of FIGURE 1 and the full line position of FIG- URE 2. The plate is moved hydraulically from the forward dotted line position to its rearward position by hydraulic cylinders indicated generally at 24 and 25. Each cylinder is pivoted at its forward end to front wall 16 by pivot pins 26 and 27, respectively. Each cylinder 3 is substantially alike and a description of one will suffice for both.

Cylinder 24 includes a main outer housing 28, an intermediate telescopic section 29, and a piston 30 which is telescopically received in intermediate section 29. A greater or lesser number of intermediate sections may be utilized depending upon the length of travel desired and other design limitations, all of which will be obvious to one skilled in the art. The outer end of piston 30 is secured by any suitable meansin this instance a plate 31 and universal joint 31ato the rear end of a preferably watertight housing 32. Housing 32 is welded to the ejector-packer plate 23 about an aperture 33 in the plate which has a diameter slightly larger than the diameter of housing 28. It will thus be obvious that when the ejector-packer plate is in itsextreme forward position the sections will telescope within one another and all sections will fit within the housing 32. The cylinders are actuated by suitable hydraulic lines indicated generally at 34 and 35.

In order to maintain the ejector-packer plate in alignment, that is moving perpendicularly to the longitudinal 'axis of the chassis, from the front to the rear, I provide a guiding mechanism, illustrated best in FIGURES 1 and 4. The ejector-packer plate mechanism includes a pair of upper guide shoes 37, 3S and a pair of lower guide shoes 39, 40. Upper guide shoes 37, 38 are triangularly shaped with their short legs welded to the action face of ejector-packer plate 23 and their long legs welded to plates 41, 42. Plates '41 and 42 slide along the undersurface of top wall 20.

The lower guide shoes 39, 40 are actually a pair of plates, whose outline is shown best in FIGURE 1, which straddle a pair of guide strips 43, 44. The shoes are.

welded at their forward end to the action face of ejectorpacker plate 23 and along their lower edge to two pairs of fiat plates 45, 46 which slide along the bottom of the body. It will be understood that the ejectonpacker plate is suitably slotted to receive the guide strips 43, 44.

Although -I have illustrated and described a pair of hydraulic cylinders, it should be understood that a greater or lesser number may be utilized. The actual amount of force needed and the location of the cylinders will depend to some extent upon the size of the unit and the operating conditions. Likewise, although a pair of guide strips which act in conjunction with guide shoes have been illustrated to provide suitable stability and alignment to the ejector plate, it will be understood that it is within the skill of the art to provide other equivalent arrangements and, accordingly, the described structure should be interpreted as illustrative only.

The ejector-packer plate 23 is apertured at either side as at 50, 51 (see FIGURE 3) to provide clearance for a pair of double-acting tailgate cylinders 53, 54. Each cylinder includes an extensible and retractable piston rod 530, 54a which is pivoted as at 55 to opposite sides of a packing plate 56. Packing plate 56 is the movable member in the packing mechanism carried by tailgate 14.

The tailgate includes a hopper 60 which terminates at its forward end in a wall 61 which lies flush against a rearwardly sloping surface 62 formed at the bottom rear end of each side wall 17 and 18. The side walls of the hopper are formed by walls 64, 65. A platform 66 is Welded to the exterior of each side of the hopper to provide a room for workmen to stand as the unit moves down an alley or collection way. A tail plate or rear wall 67 extends about two-thirds down the distance from the top of the side walls 64, 65 to thereby provide an opening 68 into which refuse may be dumped. Rear Wall 67 is curved at its upper end, as at 69, and butts against a plate 70 which extends the width of the truck. A pair of reinforcing brackets 71, 72 provide in effect lifting lugs for the tailgate. The brackets are pivoted as at 73, 74 to a pair of flanges 75, 76 which in turn are welded to a pair of guide shoe backers or stiffeners 77,

78, best shown in FIGURE 5. A pair of edge guides 80, 80 are welded to the rear tailgate plate 67 for a purpose which will appear later. A pair of hopper guides 82 are welded one to each of the side walls 64, 65, as best seen in FIGURE 5, to provide a track for a stop pin to be described later. Each of the hopper guides is welded on the inside opposing surfaces of the walls 64, 65 to provide guide means for the packer plate during that portion of its movement in which it sweeps through the opening 68.

Packer plate 56 carries a pair of edge guide rollers 84, 84- at its upper corners, as best seen in FIGURE 5. These rollers roll along the smooth inner surface defined -by rear plate 67 beneath the edge guides 80.

A pair of channel guide rollers 86 project outwardly from the edge of the packer plate, again as best seen in FIGURES 1 and 5. This pair of rollers traverses a confined, inclined path defined by a pair of packer plate guide channels 87 welded to the opposing inside surfaces of tailgate side plates 64 and 65.

The packer plate also carries a pair of edge guide rollers 88 at the two lower corners. This latter pair of rollers rolls along the inside surface of the hopper, as will be explained in the use and operation of my invention. It should be noted from FIGURE 5 that both upper edge rollers 84 and lower edge guide rollers 88 are located further inwardly toward the center of the packer plate than the channel guide rollers 86.

A pair of upper stop pins 90 project outwardly from the upper, outer edges of the packer plate. A pair of J-hooks or stops 91 receive the upper stop pins 90 in their upper rearwardmost position and prevent backward, clockwise tilting movement of the packer plate once it reaches the position of FIGURE 1. The lower edge guide rollers 88 seat in stop blocks 92 welded to side walls 17 and 18 when the packer is in its uppermost position. A pair of hopper guide valve trip pins 93 project outwardly from the edge of the packer plate between the pivot points 55 and lower edge guide rollers 88.

A typical tailgate lift block linkage is indicated gen erally at 94 in FIGURE 1. This linkage includes a hand lever 95 pivoted to the side wall 64 at 96. A long link 97 is pivoted at its lower end to hand lever 95 at 98 and at its upper end to hell crank lever 99 at 100. The bell crank is pivoted as at 101 to the outside of the frame and carries at its other end a locking pin 102. Locking pin 102 slides in a block 103 so positioned that by lifting lever 95 clockwise, the pin 102 will be projected downwardly into the packer plate guide channel 87 ahead of channel guide rollers 86 and thereby lock the packer plate 56 in position.

A pair of locking devices 104 are adapted to secure the tailgate near its lower edge to the side Walls 17 and 18 of the refuse container. Although the locking devices 104 in the drawings are mechanical, it will be within the skill of the art to utilize other arrangements to accomplish the same purpose. Solenoid operated valves might be used, for example.

My hydraulic system for actuating the double-acting ejector-packer plate, the packer plate, and the tailgate will next be described.

Referring first to FIGURE 10, the truck engine is indicated at and its transmission at 111. A power take-off is indicated at 112, a hydraulic pump at 113 and a propeller shaft at 114. The propeller shaft is universally coupled at its ends to the power take-off and hydraulic pump. A hydraulic pressure line connecting the pump 113 to main valve 115 is indicated at 116. The main valve is illustrated in greater detail in FIGURES 11, 12, 13, 14 and 15, which will be described hereinafter. A branch conduit 117 connects the main pressure line between the pump and main valve to a combination automatic tailgate and relief valve 118.

The main valve 115 is connected by a cylinder extension pressure line 119 to the end of each of ejector-packer plate cylinders 24, 25. Another pressure line, this one a cylinder retraction line, 120 is also connected to the end of each of the ejector-packer plate cylinders and opens into the main valve.

The main valve is connected by a return line 123 to reservoir 124. The reservoir in turn is connected to the pump 113 by a suction line 125. A main valve actuating lever is indicated at 126 and it will be understood that by suitable manipulation of this lever fluid will be alternately admitted into the forward end of the cylinders 24, 25 in order to move the ejector-packer plate to the rear, or bled therefrom during the loading cycle.

The double acting tailgate cylinders 53, 54- are connected to the combination tailgate and relief valve 118 by lines,129, 130 respectively. These two lines also extend rearwardly to a tailgate cylinder or packer plate actuating valve 131 located on the outside of the tailgate .and within easy reaching distance of an operator standing on the ground. It will be understood that with the addition of suitable linkage, cylinders 53, 54 can be operated from either side of the tailgate. Valve 131 is .connected to the reservoir by return line 132 and to the main valve 115 by a pressure line 133. It will be observed that lines 129 and 130 contain flexible sections 134, 135 which enables them to bend when the tailgate is elevated as illustrated in FIGURE 2. The branch conduits leading to cylinders 53, 54 are also bendable, as best seen in FIGURE 10. Valve 118 is connected to line 123 and thereby to tank 124 by a return line 136.

The actuating mechanism for packer plate valve 131 is illustrated best in FIGURES 1, 2 and 5. The linkage is indicated generally at 137 in each of FIGURES l and 2. The linkage includes a short lever. 138 which is pivoted on the inside surface of the sidewall 64 and 139. When this lever is tripped by the hopper guide trip pin 93, it causes a long link 14% to move upwardly and forwardly as viewed in FIGURE 1. The upper'end of the long link 140 is connected to a second short tripping link 141 pivoted to the side of the tailgate at 142. It will be understood that actuation of the long link 140 moves a suitable spool within valve 131 into positions in which hydraulic fluid is alternately admitted and drained from cylinders 53 and 54 to cause the packer plate 56 to move around the path illustrated in FIGURES 6-9.

The pressures exerted by the packer plate 56 on refuse placed between it and the ejector-packer plate 23 is regulated by the setting of the spring loaded relief valve 131 in a manner well known in the art. Relief valve 131 is manipulated by lever 143 which moves a spool to appropriate operating positions.

The use and operation of my invention is as follows:

Brief description of operation When my refuse collection unit begins its days run, the ejector-packer plate 23 will be in its rearwardrnost position, FIGURE 2. The tailgate will be locked in the position of FIGURE 1 by the locking devices 104. As refuse is dumped into tailgate 14 through opening 68, packer plate 56 is operated to swing down from its position of FIGURE 1 into hopper 60, scoop the refuse out of the hopper, and bring it up into the refuse collection body. By suitable manipulation of the hydraulic piping system, explained in detail hereinafter, the refuse is compacted between packer plate 56 and ejector-packer plate 23. The compacting force exerted on ejector-packer plate 23 moves it forwardly towards the cab, each increment of movement being very roughly proportional to the amount of refuse deposited and the force exerted by the cylinders 53, 54.

If at any time during the cycle it is desired to compress the refuse more tightly than is accomplished by merely pulling the packer plate 56 forwardly against the refuse and ejector-packer plate 23, pressure may be applied to cylinder 24, 25, 53, 54 simultaneously to exert an increased compacting force.

The packer plate traverses a path Whose beginning and 6 end position is illustrated in FIGURE 1, and whose intermediate positions are shown in FIGURES 6, 7, 8 and 9. Normally the packer plate will continuously cycle along the path indicated in FIGURES 1, 6, 7, 8 and 9.

At the start of a cycle, the upper stop pins 90 are seated in the I-hooks 91, and the lower edge guide rollers 88 are seated in stop blocks 92.

When hydraulic fluid is admitted to the right end of cylinders 53 and 54, piston rods 53a'and 54a are extended, thus pivoting the packer plate 56 about the channel guide rollers 36 in the channel guides 87. The packer plate swings clockwise until rollers 38 strike against the hopper guides 81} as seen in FIGURE 6.

The packer plate swings down following the contour of the hopper guides 80. Inner hopper guides 82 pick up pins 93 before edge guides 80 terminate as best seen in FIGURE 6. Intermediate the position of FIGURES 6 and 7, the lower edge guide rollers 83 strike against the lips 63a of hopper 60. It should also be noted that as soon as rollers 88 clear the back plate 67, they project outwardly away from the back plate to catch any debris which does not fit within the hopper.

In approximately the position of FIGURE 7, the valve trip pin 93 strikes the end of short link 138 of valve linkage 137. Counterclockwise movement of link 138 moves link 140 upwardly. Movement of long link 140 reverses the direction of flow of oil through packer plate valve 131 and causes oil to be admitted to the opposite end of cylinders 53, 54, thus causing piston rods 53a, 54a to retract. This condition is shown in FIGURE 8.

As the piston rods retract, upper stop pins 90 contact the hopper guides 82, and the lower edge guide rollers roll along the hopper 6t} and walls 62 of the tailgate.

The packer plate pivots around channel guide rollers 86 which are seated in the lower ends of the guide channels 87. This condition is best seen in FIGURE 8.

Continued retracting movement of rods 53a, 54a causes the packer plate to move upwardly lifting the refuse ahead of it as seen in FIGURE 9. During this movement, rollers 84 contact guides 80.

Near the completion of the retracting movement of the piston rods, the lower edge guide rollers seat in stop blocks 92. The valve trip pins 93 then strike upper" short link 141 of valve linkage 137 causing long link 140 to be moved downwardly. Movement of long link 140 downwardly reverses valve 131, and drains fluid from the lower end of pistons 53, 54, and admits fluid to their upper ends, causing the cycle to begin again.

At the end of the run, locking devices 104 are released, the tailgate mechanism is raised to the position of FIG- URE 2 by actuating lever 143 and the ejector-packer plate 23 is forced rearwardly by admitting hydraulic fluid to the appropriate inlet ports in cylinders 24, 25. When the ejector-packer plate 23 moves to the position of FIG- URE 2, the tailgate is lowered and my refuse collection unit is ready to begin another run.

Valve operation The three operating positions of the main valve are illustrated in FIGURES 11 through 13. valve 131 and tailgate valve 118 are identical in construction and operation to the main valve 115, except the passage in the valve body opening into what would be equivalent of line 117 is plugged in each valve. A description of the fluid flow in the three operatingpositions of the main valve will therefore suffice for a description of all three valves.

Assume the ejector-packerplate is at the forward end of the truck body adjacent cab 11. To drive it to the rear, valves 131 and 118 would be in the PACK position of FIGURE 11. In this position, fluid entering port D enters passageway H of the spool S and goes into port P which is blocked by a plug, not shown, in each instance. Therefore valves 131 and 118 are removed from the hydraulic circuit. It will be understood that when Packer plate main valve 115 is in the PACK position, valves 131 and 118 are effectively removed from the circuit, and it is immaterial what position the latter two valves are in.

To drive the ejector-packer plate 23 to the rear, main valve 115 is thrown to the EXTEND position of FIGURE 13 by lever 126. The power takeolf 112 and pump 113 are running. Fluid under pressure enters through line 116 and passageway L. It is blocked at K and J by valve body R, and at E by the pressure relief valve 145. Fluid passes from L through passageway G through port B and out conduit 119 to the extend conduits at the front end of cylinders 24, 25. These cylinders are hydraulic double acting telescoping cylinders whose basic operation is well known in the art. So long as the pressure in the cylinders does not exceed the setting of the pressure relief valve 145, hydraulic fluid merely passes through the main valve and extends the telescoping cylinder. If the pressure exceeds the setting of the pressure relief valve, the valve is unseated and a small amount of fluid passes by a passageway Q into a tank return passageway M connected to return line 123 which dumps into the tank.

The residual oil in the double acting hydraulic telescoping cylinders which is forced out by the extension of the cylinders enters main valve 115 through conduit 12%, port A, thence to the valve spool passageway H and down to return lines and M in the spool and valve body R.

To retract the ejector-packer plate from its fully extended position, handle 126 rotates the valve spool S 45 degrees counterclockwise to the retract position of FIG- URE 12. The power take off and the pump continue to run. In this position hydraulic fluid entering port D and passageway K passes directly into conduit 120 via passageway G and port A. The volume of oil flow will probably be considerably less than when the valve operates in the EXTEND position. Oil displaced from the telescopic cylinders enters the valve body R from conduit 119 at port 13, passes into passageway F, and drops down wardly into discharge passage M connected to return line 123 which dumps into tank. Note that the fluid will not flow through passageway 0 because it is blocked ofl by the lower edge of the valve spool. The relief valve functions in the same way, i.e., if the pressure in the valve exceeds the setting of the relief valve, fluid will enter passageway L, unseat the valve and go via passageway Q into return line 123.

Now assume that the ejector-packer plate is at its rearwardmost position or just a short distance inwardly so as to permit clearance of the cylinder 24, and it is desired to let the ejector-packer plate move forwardly under the impetus of the compacting force from the packer plate.

Forgetting for the moment the operation of valve 131, main valve 115 is turned to the PACK position of FIG- URE 11. Hydraulic fluid under pressure enters port D, flows through passageway H and goes into discharge port P which feeds the packer plate valve 131 through conduit 117. Fluid flow into the tailgate valve 118 is blocked as will be described later.

As the packer plate pushes against the refuse which in turn pushes against the ejector-packer plate forcing it forwardly, oil enters valve body R at port B. It is blocked off from all paths except through the relief valve 145. As soon as the pressure in the valve exceeds the setting of the relief valve, the valve will unseat and oil will feed through by-pass Q into discharge passageway M. The relief valve 145 acts as a restricted flow orifice which exerts a yielding, hydraulic pressure force against the plate. A small amount of fluid may circulate through the valve and leave via port A to fill voids in the retracting oil chambers formed as the cylinders telescope within one another.

When the system is used to run the packer plate, valve 118 is turned to the PACK position of FIGURE 11, thus taking it out of the circuit since port P is plugged off. Main valve 115 is turned to the PACK position, and packer plate valve 13*]. is operated from the EX- TEND and RETRACT positions of FIGURES 13 and 12. The EXTEND and RETRACT positions on valve 131 work identically to the EXTEND and RETRACT positions of main valve 115. In this instance the valve is automatically flipped from EXTEND to RETRACT by the pins 93 carried by the packer plate itself, as described earlier.

The above description has been based on the fact that the packer plate is continuously operable, i.e., as it comes down it trips the valve linkage 137 which in effect cocks the system so that when the packer plate reaches the position of FIGURE 1 it will again trip the valve linkage system and send the packer plate downwardly.

In order to convert to manual operation, the upper short link 142 would be omitted or, alternatively, it could be hinged so that it would continue to operate automatically so long as the hinge is unbroken, but, when broken, the packer plate could onlybe run through one cycle.

For emergency purposes, the valve 131 can be flipped from EXTEND to RETRACT or vice-versa at any time during the cycle by merely flicking the long link 1140. If, for example, a workmans hand is caught in the hopper or something is dumped in which should not have been dumped in, the packer plate can be stopped at any point in the cycle and its direction of travel reversed. Likewise, by judging the feel on the link 149, the packer plate can be stopped. ondead center. A dedent mechanism can be added to the link to indicate dead center.

Now assume that the ejector-packer plate is at the forward end of the truck body and the truck has backed to the dump preparatory to dumping its load. The bell crank lever system 94 is actuated to lock the upper setof rollers 86 into the position shown on FIGURE 1. That is, handle 95 is moved clockwise, and pin 102 thrust into the guide channel 37. Valve 131 is thrown to the PACK position. In this position it is effectively taken out of the circuit because the passageway P is blocked off by a plug, as mentioned earlier. Main valve is likewise thrown to the PACK position, but since there is no plug in outlet P fluid just circulates directly from the pump through the main valve to the tailgate valve 118. The tailgate is operated by moving lever 143 to the EX- TEND and RETRACT positions. The valve operation in these posit-ions is identical to the corresponding positions of the main valve.

To raise the tailgate, valve 118 is thrown to the EX- TEN D position. Fluid then enters port D, and the fluid flow is identical to that described earlier.

With the tailgate elevated the ejector-packer plate must be moved rearwardly to push out the load. To move the ejector packer plate while the tailgate is elevated, the main valve 115 is thrown to the EXTEND position. This efifectively traps all of the oil in the circuit leading to valve 118 so the tailgate cannot come down. Ejectorpacker plate then moves rearwardly, as earlier described.

Now, assume that the tailgate is still elevated and the ejector-packer plate has been moved to its desired position at the rear end of the truck preparatory to receiving the next load. Valve 118 is thrown to RETRACT position which opens the oil trapped in the valve 'to the tank through ports B and A and out passageway M. The weight of the tailgate forces the oil out. It .is desirable that main valve 115 be in the PACK position as the tailgate drops downwardly under the force of gravity. As the tailgate drops downwardly it pushes oil ahead of the advancing piston in the cylinders and may create a vacuum behind the pistons. By maintaining a positive pressure force entering the RETRACT position of valve 118, the possibility of creating a vacuum is decreased.

Any time valves 118 and 13 1 are operating, main valve 115 should be in the PACK position.

Any time valve 131 is operating, valve 118 should be in the PACK position.

Any time valve 118 is operating, tailgate valve 131 should be in the PACK position.

It should also be understood that although I have indicated the valves and linkage 94 :as handlever operated, either or both could be solenoid operated within the skill of the art.

Although a preferred embodiment has been illustrated and described in some detail, it should be understood that the description is illustrative only, as many changes could be made by one skilled in the art Without departing from the spirit ofthe invention. Accordingly, the scope of the invention should only be limited by the scope of the appended claim.

I claim:

A refuse collection unit, said unit including, in combination,

a storage body,

a movable, combination ejector-packer plate within the storage body constructed and arranged to traverse the body,

means for imparting a generally rear wardly directed yieldable, resisting force to the epector-packer plate,

means for maintaining the ejector-packer plate substantially perpendicular to the longitudinal axis of the storage body as the ejector-packer plate traverses the body, said means for maintaining the ejector-packer plate substantially perpendicular including a pair of generally vertically oriented telescoping hydraulic cylinders connected to the ejector-packer plate, one connected to the ejector-packer plate adjacent its top and the other adjacent its bottom whereby tilting of the ejector-packer plate about a generally horizontal axis is prevented,

stabilizing means for preventing skewing of the ejectorpacker plate about a vertical axis, said stabilizing means including a pair of members carried by the refuse storage body, one on each side of the pair of generally vertically oriented telescoping cylinders,

said pairs of members being cooperable with sub-' 10 stantially complementary openings in the ejectorpacker plate, a tailgate mechanism connected to the rear of the refuse storage body, said tailgate mechanism including, a hopper, a packer plate cooperable with the hopper and operable to move ref-use deposited in the hopper against the ejectonpacker plate, and means for moving the packer plate through a path in which it terminates in a position substantially opposed to the ejector-packer plate, means associated with the packer plate operable to exert a packing force against refuse deposited between it and the ejector-packer plate which is greater than the resisting force exerted by the ejector-packer plate whereby the ejector-packer plate is forced forwardly in response to the unbalanced packing force exerted by said packer plate, means for elevating and lowering the tailgate mechanism, and means for moving the ejector-packer plate rearwardly to discharge refuse deposited'in the refuse storage body while the tailgate is elevated.

References Cited by the Examiner UNITED STATES PATENTS GERALD M. FORLBNZA, Primary Examiner.

ERNEST A. FALLBR, Examiner. S. GRAYSON, Mt- TEMIN, Assistant Examiners. 

